ALMI's window box planters are made of strong plastic materials. Therefore; the product is really durable. Other than that, ridged sides provide sturdiness and durability too. This plastic box planter is such a lightweight and fade-resistant product. You can use this as a standalone flower box or as a liner inside planters. This is ideal for those who are passionate in gardening. In addition; this window box planter is great addition to your windows.